Baton Rouge - The head of the NAACP in Baton Rouge called on Wednesday for the police chief to be fired after a Louisiana police officer shot and killed a black man during a confrontation outside a convenience store."What I'm calling for today is that the chief law enforcement officer to fire the police chief," Michael McClanahan said. "He must step down. We cannot have anybody who allows this type of action to take place."A video that purported to show the killing of Alton Sterling further fuelled public anger about the shooting on Tuesday, prompting hundreds to protest. The protest lasted into the night, with people chanting and holding up signs.The Associated Press has not been able to authenticate the video. But the appearance of the store in the video matches the front of convenience store where the shooting occurred. The man being subdued by police was wearing a red shirt, matching the description given earlier by police.In the video, which appears to be shot from inside a nearby parked car, one of two police officers outside the store can be seen tackling the man in the red shirt and wrestling him to the ground. Then the other officer helps him hold the man down.At one point someone can be heard saying, "He's got a gun! Gun!" and then one officer on top of the man can be seen pulling his weapon from his holster. After some shouting, what sounds like a gunshot can be heard and the camera pulls away. Then another four shots can be heard. At one point, a person in the vehicle asks "They shot him?" as a woman can be heard crying.'Black lives matter'The Advocate reported the crowd that gathered late on Tuesday afternoon at the store where Sterling died grew to more than 200 people. They chanted "black lives matter" and "hands up don't shoot" and waved signs late into the night, according to the newspaper.By dawn on Wednesday, protesters and friends had created a makeshift memorial to Sterling on the white folding tables and fold out chair he had used to sell home made music compilations on CD's.Arthur Baines came by to pay his respects. He said Sterling had stayed with his sister at some point."He never bothered nobody. He was just trying to make an honest dollar," Baines said. He said he thought Sterling was out late on July 4th because more people were out on the holiday: "That's really how he made all of his money,"Mufleh Alatiyat, a 25-year old employee of the store described Sterling as generous and said he often gave away CDs or petty cash or bought food or drink for some people."He was a very nice guy," he said. "He helped a lot of people."An autopsy shows Sterling died of multiple gunshot wounds to the chest and back, East Baton Rouge Parish Coroner Dr. William Clark said.Altercation Officers responded to the store about 00:35 on Tuesday after an anonymous caller indicated a man selling music CDs and wearing a red shirt threatened him with a gun, Corporal L'Jean McKneely said.Two officers responded and had some type of altercation with the man and one officer fatally shot the suspect, McKneely said. Both officers have been placed on administrative leave, which is standard department policy, he said.The store's owner, Abdul Muflahi, told WAFB-TV that the first officer used a stun gun on Sterling and the second officer tackled the man. Muflahi said as Sterling fought to get the officer off of him, the first officer shot him "four to six times".The owner said Sterling did not have a gun in his hand at the time, but he saw officers remove a gun from Sterling's pocket after the shooting.McKneely said late on Tuesday that he could not confirm Muflahi's description of the event or any other details of the investigation.Kimberly Lang said she purchased CDs from Sterling on occasion and said he did not have a reputation for violence, according to a report by NOLA.com/The Times-Picayune.If Sterling did have a gun on him, Lang said, it was probably because he feared being robbed while peddling his CDs late at night, not because he wanted to threaten anyone.